Recoil shock absorber for a shoulder firearm

ABSTRACT

A recoil shock absorber for a shoulder firearm in which the butt of the firearm is divided into two parts which are spaced from each other in the longitudinal direction of the firearm and are connected to each other on the outer side of the butt by an elastic sleeve, for example, of leather or plastic, and in which the shock absorber comprises a multiple-disk friction brake, one set of brake disks of which is frictionally rotatable relative to the other set, an overrunning roller clutch which is engaged during the recoil of the firearm while the two butt parts move toward each other against the action of the brake and which is disengaged when the recoil is terminated, and spring means of a strength just sufficient for then returning the shoulder-engaging butt part to its original position.

United States Patent [191 Kuhl [ RECOIL SHOCK ABSORBER FOR A SHOULDER FIREARM [75] Inventor: Hans Kuhl, Plochingen, Germany [73] Assignee: Wolfgang Kammerer, Holzmaden,

Germany; a part interest 22 Filed: Apr. 17, 1972 21 Appl. No; 244,700

[30] Foreign Application Priority Data Apr. 22, 1971 Germany 2119648 [52] US. Cl. 42/74 [51] Int. Cl. F416 23/00 [58] Field of Search 42/74; 89/42 R, 158, 198

[56] References Cited UNITED STATES PATENTS 837,601 12/l906 Bchr 42/74 910,276 1/1909 Easdale.... 42/74 935,822 10/1909 Schmidt 42/74 3,208,179 9/1965 Hrebicek 42/74 FORElGN PATENTS OR APPLICATIONS 1 19,460 4/1901 Germany 89/42 R [4 1 Mar. 12, 1974 Primary ExaminerBenjamin A. Borchelt Assistant Examiner-C. T. Jordan l 5 ABSTRACT A recoil shock absorber for a shoulder firearm in which the butt of the firearm is divided into two parts which are spaced from each other in the longitudinal direction of the firearm and are connected to each other on the outer side of the butt by an elastic sleeve, for example, of leather or plastic, and in which the shock absorber comprises a multiple-disk friction brake, one set of brake disks of which is frictionally rotatable relative to the other set, an overrunning roller clutch which is engaged during the recoil of the firearm while the two butt parts move toward each other against the action of the brake and which is disengaged when the recoil is terminated, and spring means of a strength just sufficient for then returning the shoulder-engaging butt part to its original position.

16 Claims, 5 Drawing Figures PATENTEDHAR 12 I974 SHEET10F3 RECOIL SHOCK ABSORBER FOR A SHOULDER FREARM The present invention relates to a recoil shock absorber for a shoulder firearm for taking up the recoil of a rifle, shotgun or similar firearm so as to reduce the impact of the butt of the gun against the shoulder of a hunter or rifleman. For mounting this shock absorber, the butt of the gun is divided into two parts which are slidable relative to each other in the longitudinal direction of the gun and the elements of the shock absorber which are located within a recess between these two parts are supported on the latter.

The shock absorbers of this type as are presently known usually consist of springs and/or of pneumatic or hydraulic cylinder and piston units. In place of springs, it is also known to provide an element of a resilient material between and connecting the two parts of the gun butt. All of these shock absorbers have, however, the disadvantage that they are only capable of taking up a very small amount of the energy of the recoil of the guns, that their shock absorbing effect is therefore very small and that, when the recoil is transmitted by them to the part of the butt which the rifleman presses against his shoulder, a series of jarring impacts will be exerted thereon. The insufficient absorption of the energy of the recoil and the occurrence of jarring impacts upon the shoulder of the rifleman will not only be painful to the latter but his unconscious fear of these impacts and this pain may affect his aim so that, for example, in hunting, he may only wound the game and these animals may subsequently die very painfully.

It is an object of the present invention to provide a shock absorber for a rifle, shotgun or a similar firearm which is of the type as first described above but is capable of absorbing the recoil of a gun more effectively than this has been possible by the shock absorbers as previously devised. For attaining this object, the invention provides the shock absorber in the form of a friction brake.

A friction brake as a shock absorber of a gun has the advantage that it does not merely accumulate the energy of the recoil which is exerted upon it but that it converts this energy into heat and thus prevents the occurrence of succession of jarring blows upon the shoulder of the rifleman. Furthermore, a friction brake has the advantage that, even though it only needs to take up a small space, it absorbs a considerable part of the recoil energy. This is true particularly if the friction brake is provided according to a preferred embodiment of the invention in the form of a multiple-disk brake, one set of brake disks of which is rotatable relative to the other against the friction between the two sets of brake disks. If the recoil of the gun is smaller than the distance between a telescopic sight which is mounted on the gun and the head of the gunner, it is possible without any difficulty to convert 75 percent of the recoil energy into heat. The rifleman therefore has to take up no more than 25 percent of this recoil energy.

It is a further advantage of a multiple-disk brake as a shock absorber that the braking force may be very easily varied by changing the axial pressure which is exerted upon the brake disks. Such an adjustment of the braking force may also be easily carried out when the shock absorber is already installed in the butt of the gun. This is, for example, of advantage if the rifleman wishes to change the braking force from time to time because he intends to use a different sort of ammunition. He may thus vary the braking force even to such an extent that the shock absorption may be adapted to the use of cartridges of any caliber or explosive force.

The relative movements of the two parts of the butt are preferably transmitted to the brake by means of a rack which may at the same time serve the function of guiding the two parts of the butt relative to each other. According to one preferred embodiment of the invention which is very advantageous because of the small amount of space which it requires and because of the small mass and dimensions of its parts which rotate during the shock absorption, the peripheral surface of one set of the disks of the brake is provided with radial teeth which mesh with the rack teeth. Of course, instead of such a structure, the brake disks may also be nonrotatably inserted into a gear ring which is provided with radial teeth which mesh with the rack teeth.

It is another important object of the invention to provide suitable means for insuring that the brake will only be effective during the recoil of the gun, but will not exert any brake force during the return of the two parts of the butt to their original positions. According to a preferred embodiment of the invention, this object is attained by providing an adjustable clutch, preferably an overrunning roller clutch, which may either be mounted between the multiple disk brake and the housing containing the same or between the disk brake and the rack. In the first case, the outer race of the clutch may carry one of the sets of brake disks, while in the second case the inner race of the clutch may carry one set of brake disks and the outer race may be provided with the teeth which mesh with the teeth of the rack.

The features and advantages of the present invention will become more clearly apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIG. 1 shows a longitudinal section which is taken along the line I I of FIG. 2 of a part of a gun butt containing a shock absorber according to a first embodiment of the invention;

FIG. 2 shows a cross section which is taken along the line II II of FIG. 1;

FIG. 3 shows a longitudinal section which is taken along the line III III of FIG. 4 of a part of a gun butt containing a shock absorber according to a second embodiment of the invention; while FIG. 4 shows a cross section which is taken along the line IV IV of FIG. 3;

FIG. 5 is a view in perspective illustrating the disposition of the recoil shock absorber of this invention in a firearm.

Referring first to FIGS. 1 and 2 of the drawings, the butt I of a rifle, shotgun or similar firearm comprises a first butt part 2 which has an outer shape similar to that of the corresponding part of a conventional butt which is not provided with a shock absorber and the end of which, broken away and not shown, carries the barrel of the rifle or the like. This butt part 2 which may consist, for example, of wood, is provided with a recess in its rear end 3 into which a metallic housing 4 is inserted so that, with the exception of its rear, outwardly projecting flange 13, this housing 4 is completely embedded within the wooden butt part 2 and rigidly secured thereto by screws 15 which extend through the flange 13.

This housing 4 has a substantially rectangular cross section and its one wider side and its narrow rear end inwardly of the flange 13 are open. The narrow upper and lower sides of housing 4 are integral with a pair of parallel hollow cylindrical guide tubes 5 and 6 which project beyond the main front wall of the housing in the direction toward the barrel into corresponding recesses in the first butt part 2. The longitudinal axes of these guide tubes 5 and 6 extend parallel to each other and parallel to the longitudinal axis of the barrel of the gun.

Each of these guide tubes 5 and 6 contains a guide rod 7 or 8, respectively, which is slidable in its axial direction and guided by the wall of the respective tube. The ends of both rods 7 and 8 which project toward the rear from the guide tubes 5 and 6 are rigidly secured to a second butt part 9 which has an outer peripheral shape so as to form a continuation of the contours of a first butt part 2 and consists of a metallic plate 10 of a sufficient rigidity and a shoulder plate 111 which covers and is connected to the rear side of plate It) and consists of a material of a certain resilience like the shoulder plate of a conventional gun butt and the rear side of which is also slightly concave in the usual manner.

The second butt part 9 is movable from its basic position as shown in FIG. 1 relative to the first butt part 2 to an extent which is limited by the axial length of the cylindrical guide tubes 5 and 6 and the rods 7 and 8. In the particular embodiment of the invention as illustrated in FIG. I, the extent of this moveability is made slightly smaller than the distance at which a telescopic sight which might be mounted on the gun would be spaced from the head of a person aiming the gun. The basic position of the second butt part 9 is further determined by the length of an elastic sleeve 12 which may consist, for example, of leather or plastic. The front edge of this sleeve I2 is clamped between the rear end surface 3 of the first butt part 2 and the flange 113 on the open rear side of the housing 4, which the rear edge of sleeve 12 is clamped between the two plates 10 and 11 of the second butt part 9. The part of guide rod 7 which projects from the guide tube 5 is surrounded by a coil spring M the opposite ends of which abut with an initial pressure against the flange l3 and the plate 10. This coil spring 14 forms a return spring which tends to maintain the second butt part 9 together with the guide rods 7 and it in their basic position and returns them to this basic position after they have been moved toward the first butt part 2. Coil spring 14 is, however, made of only a relatively low strength so as not to cause any succession ofjarring impacts upon the shoulder of the rifleman.

In order to reduce considerably the energy of the recoil of the gun which when the gun is shot is transmitted from the first butt part 2 to the second butt part 9, a multiple-disk brake 116 is mounted in the housing 4 This multiple-disk brake I6 is adapted to convert the largest part of the recoil energy into frictional heat and it also prevents the occurrence of repeated jarring blows upon the shoulder of the rifleman.

As shown in FIG. 2, the brake disks of one set are provided with diametrically opposite inner projections which engage into corresponding longitudinal grooves 18 in the outer surface ofa hollow hub l7 and are thus non-rotatably connected thereto. The axis of this hub extends vertically to the central longitudinal plane of the first butt part 2 within which the axes of the two guide tubes 5 and 6 and guide rods 7 and 8 are also located. One end of this hollow hub 17 is fitted through an aperture in the side wall 119 of housing 4 and is rigidly secured to this wall 119, while upon the inner wall of this wall 19 a flange 20 engages which is secured to the hub l7 and the other side of which laterally supports the brake disks of the inner set.

The brake disks of the other or outer set which alternate with the brake disks of the inner set are provided with radial projections which engage into longitudinal grooves 2i in a ring 22 which extends coaxially to the hub l7.

The inner and outer brake disks are pressed against each other by means of a screw 23 which is screwed into an internal thread in the hollow hub 17 and the head of which acts upon a cup spring 24 via a washer 25 which, in turn, presses against the last brake disk of one set. By means of this screw 23 it is possible to vary the axial pressure with which the brake disks are pressed against each other and thus to vary the braking force of the multiple-disk brake 16. As shown in FIG. 2, the outer surface of the head of screw 23 which is preferably provided with a hexagonal recess for the insertion of a suitable tool is rotatably guided within a bushing 26 which is secured in a bore in one side wall of the butt part 2. For preventing any dust or moisture from entering the housing 4, a resilient gasket 27 is inserted into an annular groove in the head of screw 23 and its outer surface fits tightly against the inner wall of bushing 26.

Ring 22 forms the inner race of an overrunning roller clutch, the outer race 28 of which is provided on its outer periphery with spur teeth 29 which mesh with rack teeth 30 which are milled into the side of the lower guide rod 8 which faces the brake 16.

The overrunning clutch, the rollers 31 of which are guided at their opposite ends by rings 32, is designed so as to connect the outer race 28 nonrotatably to the ring 22 when the outer race 28 turns in a clockwise direction, as seen in FIG. 1. Therefore, if due to the recoil of the gun the first butt part 2 tends to move toward the second butt part 9, this movement can only be carried out insofar as it overcomes the braking force of the multiple-disk brake 16 since the guide rod 3 then penetrates into the associated guide tube 6 and thereby turns the outer race 28.

The return movement of the second butt part 9 away from the first butt part 2 and back to its original position as shown in FIG. 1 will be effected by the coil spring 14 since the outer race 2% of the overrunning clutch can turn freely in its opposite direction, that is, in its counterclockwise direction as seen in FIG. 1.

FIGS. 3 and 4 illustrate a second embodiment of the invention which differs from the embodiment according to FIGS. 1 and 2 essentially only by a slightly different construction of the multiple-disk brake 1116. All of the other parts which are hereafter not particularly described may therefore be substantially equal to those as shown in FIGS. l and 2 and, insofar as they are designated by numerals, these numerals are increased by over those as applied in FIGS. l and 2.

The hollow hub 1117 is provided at one end with a flange which is inserted into a countersunk bore in the side wall of housing MM and riveted together with this wall so as to be rigidly secured to the housing MM.

As shown in FIG. e, the hollow hub forms the inner race of the overrunning roller clutch, the outer race 128 of which is provided with longitudinal grooves 118 into which radial projections engage which are provided on one set of disks of the disk brake l 16. The rol lers 131 of the overrunning clutch are guided within and by a cage 133 which is disposed between the flange 120 and a flange 134 on a threaded bushing 135 which is inserted into the hollow hub 117. These two flanges 120 and 134 also guide the outer race 128 in both lateral directions. A screw H36 maintains the flange 134 in engagement with the flangeless end of the hollow hub 117.

The overrunning roller clutch according to FIGS. 3 and 4 is designed like the clutch as shown in FIGS. 1 and 2 so that, when the outer race 128 is turned in the clockwise direction as seen in FIG. 3, the clutch is engaged, while it is released when the outer race 128 is turned in the opposite direction.

The end of the outer race 128 which is located at the same side as the flange 120 is provided with an annular flange 138 which braces the brake disks at this side. At the opposite side of the brake disks, the axial pressure is applied upon them via a washer 125 and a cup spring 124 by a screw 123 which is screwed into the bushing 135. The head of this screw 123 is not accessible from the outside and the braking force of this multiple-disk brake is therefore not adjustable unless the housing 104 is first removed from the gun butt. Of course, it would also be easily possible in this case to provide the side wall of the wooden butt part with a bore through which the head of screw 123 may be adjusted from the outside.

The brake disks of the set which is rotatable relative to the other set which is mounted on the outer race 128 are provided on their outer peripheral surface with spur teeth 129 which mesh with the rack teeth 130 of the lower guide rod 108. For insuring that the rack teeth 130 engage with the teeth of all of the rotatable brake disks, the lower guide rod 108 is made of a larger diameter than the upper guide rod 107.

This particular construction of the multiple-disk brake and of the overrunning roller clutch as illustrated in FIGS. 3 and 4 permit the distance between the two guide rods 107 and 108 to be reduced without requiring the width of the housing 104 in the axial direction of the disk brake to be increased so that this brake and clutch may be mounted even within relatively small rifle butts.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

l. A shock absorber for a shoulder firearm comprising a butt divided into at least two parts guided on and movable relative to each other in the longitudinal direction of said firearm and normally spaced from each other, and a friction brake disposed within and guided by said two butt parts and having two brake means frictionally engaging with each other, one of said brake means being connected to one of said butt parts and the other brake means being connected to the other butt part.

2. A shock absorber as defined in claim 1, in which said friction brake comprises a multiple-disk brake and each of said brake means comprises a set of brake disks, the lateral sides of said disks of each set frictionally engaging with the lateral sides of the adjacent disks of the other set.

3. A shock absorber as defined in claim 2, further comprising means for adjusting the frictional engagement between said two sets of brake disks so as to vary the braking force of said brake.

4. A shock absorber as defined in claim 2, further comprising means for coaxially mounting said two sets of brake disks on a first of said butt parts about an axis extending transverse to said longitudinal direction, the first of said sets being rigidly connected to said first butt part and the second set being frictionally connected to and rotatable relative to said first set, and gear means connecting said second set to said second butt part.

5. A shock absorber as defined in claim 4, in which said gear means comprise a gear rim secured to the outer periphery of said first set, and a rack secured at one end to said second butt part and forming an element for guiding said two butt parts in said longitudinal direction relative to each other and having teeth in mesh with the teeth of said gear rim.

6. A shock absorber as defined in claim 5, in which said gear rim comprises corresponding gear teeth on said first set engaging with the teeth of said rack.

7. A shock absorber as defined in claim 4, in which said gear means comprise a bushing having outer spur teeth and rigidly secured to and surrounding all of said brake disks of said first set and being in mesh with said teeth of said rack.

8. A shock absorber as defined in claim 5, further comprising guide means in said first butt part, said rack being slidable in said longitudinal direction in and guided by said guide means.

9. A shock absorber as defined in claim I, further comprising clutch means having two clutch members interposed between said brake means and one of said butt parts, and means for locking said clutch members together when under the recoil of said firearm said two butt parts tend to move from a basic distended position toward each other against the action of said brake and for releasing said clutch members from each other when said recoil is terminated, and means for then returning said butt parts to said basic position.

10. A shock absorber as defined in claim 9, in which said clutch means comprise an overrunning roller clutch.

111. A shock absorber as defined in claim 9, in which said return means comprise at least one return spring between said two parts having a strength just sufficient for returning said butt parts to their original position when said recoil is terminated and said clutch members are released.

12. A shock absorber as defined in claim 4, further comprising a housing rigidly secured to the first of said butt parts and having a central recess, and two parallel hollow cylindrical guide tubes at the opposite sides of said recess and integral with said housing, said disk brake being mounted on said housing within said recess, the axes of said guide tubes extending transverse to the axis of said brake and within a common plane intersecting the axis of said brake, a guide rod axially slidable within and guided by each of said guide tubes and having one end secured to the second butt part, said gear means comprising a rack formed by rack teeth on at least a part of the length of one of said guide rods.

13. A shock absorber as defined in claim 12, in which said gear means comprise said gear teeth on the periphery of said first set of brake disks and meshing with said rack teeth, and clutch means having an outer race and an inner race, said second set of brake disks being secured to said outer race, and said inner race forming a hub which is nonrotatably connected to said housing.

14. A shock absorber as defined in claim 12, and clutch means comprising an outer race and an inner race, said outer race having spur teeth on its outer periphery meshing with said rack teeth, said inner race nonrotatably connected to one of said sets of brake disks, and a central hub nonrotatably connected to said housing, the other set of brake disks being mounted on and nonrotatably connected to said hub.

15. A shock absorber as defined in claim 12, including a barrel, said housing including said guide tubes is embedded in said first butt part which also carries said barrel, said housing having an outwardly projecting flange on its rear end, and means for securing said flange to the rear end of said first butt part.

16. A shock absorber as defined in claim 1, further comprising a sleeve of an elastic material connecting said two butt parts to each other. 

1. A shock absorber for a shoulder firearm comprising a butt divided into at least two parts guided on and movable relative to each other in the longitudinal direction of said firearm and normally spaced from each other, and a friction brake disposed within and guided by said two butt parts and having two brake means frictionally engaging with each other, one of said brake means being connected to one of said butt parts and the other brake means being connected to the other butt part.
 2. A shock absorber as defined in claim 1, in which said friction brake comprises a multiple-disk brake and each of said brake means comprises a set of brake disks, the lateral sides of said disks of each set frictionally engaging with the lateral sides of the adjacent disks of the other set.
 3. A shock absorber as defined in claim 2, further comprising means for adjusting the frictional engagement between said two sets of brake disks so as to vary the braking force of said brake.
 4. A shock absorber as defined in claim 2, further comprising means for coaxially mounting said two sets of brake disks on a first of said butt parts about an axis extending transverse to said longitudinal direction, the first of said sets being rigidly connected to said first butt part and the second set being frictionally connected to and rotatable relative to said first set, and gear means connecting said second set to said second butt part.
 5. A shock absorber as defined in claim 4, in which said gear means comprise a gear rim secured to the outer periphery of said first set, and a rack secured at one end to said second butt part and forming an element for guiding said two butt parts in said longitudinal direction relative to each other and having teeth in mesh with the teeth of said gear rim.
 6. A shock absorber as defined in claim 5, in which said gear rim comprises corresponding gear teeth on said first set engagIng with the teeth of said rack.
 7. A shock absorber as defined in claim 4, in which said gear means comprise a bushing having outer spur teeth and rigidly secured to and surrounding all of said brake disks of said first set and being in mesh with said teeth of said rack.
 8. A shock absorber as defined in claim 5, further comprising guide means in said first butt part, said rack being slidable in said longitudinal direction in and guided by said guide means.
 9. A shock absorber as defined in claim 1, further comprising clutch means having two clutch members interposed between said brake means and one of said butt parts, and means for locking said clutch members together when under the recoil of said firearm said two butt parts tend to move from a basic distended position toward each other against the action of said brake and for releasing said clutch members from each other when said recoil is terminated, and means for then returning said butt parts to said basic position.
 10. A shock absorber as defined in claim 9, in which said clutch means comprise an overrunning roller clutch.
 11. A shock absorber as defined in claim 9, in which said return means comprise at least one return spring between said two parts having a strength just sufficient for returning said butt parts to their original position when said recoil is terminated and said clutch members are released.
 12. A shock absorber as defined in claim 4, further comprising a housing rigidly secured to the first of said butt parts and having a central recess, and two parallel hollow cylindrical guide tubes at the opposite sides of said recess and integral with said housing, said disk brake being mounted on said housing within said recess, the axes of said guide tubes extending transverse to the axis of said brake and within a common plane intersecting the axis of said brake, a guide rod axially slidable within and guided by each of said guide tubes and having one end secured to the second butt part, said gear means comprising a rack formed by rack teeth on at least a part of the length of one of said guide rods.
 13. A shock absorber as defined in claim 12, in which said gear means comprise said gear teeth on the periphery of said first set of brake disks and meshing with said rack teeth, and clutch means having an outer race and an inner race, said second set of brake disks being secured to said outer race, and said inner race forming a hub which is nonrotatably connected to said housing.
 14. A shock absorber as defined in claim 12, and clutch means comprising an outer race and an inner race, said outer race having spur teeth on its outer periphery meshing with said rack teeth, said inner race nonrotatably connected to one of said sets of brake disks, and a central hub nonrotatably connected to said housing, the other set of brake disks being mounted on and nonrotatably connected to said hub.
 15. A shock absorber as defined in claim 12, including a barrel, said housing including said guide tubes is embedded in said first butt part which also carries said barrel, said housing having an outwardly projecting flange on its rear end, and means for securing said flange to the rear end of said first butt part.
 16. A shock absorber as defined in claim 1, further comprising a sleeve of an elastic material connecting said two butt parts to each other. 